The piping from cleaning and storage tanks which store aqueous solutions frequently are exposed to the elements of weather. An aqueous solution leak detection system for such piping therefore needs to be water resistant but must still be able to detect the presence of water in a solution. Aqueous solutions frequently have detergents in them, and it would be beneficial to have a leak detection system that was based on the presence or absence of a surfactant in the leaking liquid. This is especially true for aqueous acids or bases that contain a surfactant. Many systems for detecting leaking acids or bases depend on the corrosive effect of the acid or base on a metal conductor for detection means. For example, EPA 017174 measures a capacitance change that occurs upon destruction of an aluminum shield when the cable is attacked by acid; and in PCT WO 89/05446 an insulation between two conductors is impregnated with an acid-sensitive additive which reacts with acid and changes the impedance of the insulation. However, such systems tend to act only slowly or only with concentrated acids and may be liable to breakdown through contact with environmental corrosives.